During a lengthy testimony in front of the FIA International Tribunal in Paris on Thursday, Mercedes conceded that there were elements of the test that it wished had been done differently.
In particular, it says the way that Lewis Hamilton and Nico Rosberg wore unmarked plain black helmets to avoid security issues with fans was a mistake and propagated the view of a conspiracy of silence.
Mercedes lawyer Paul Harris QC said: "We can see now, with the benefit of hindsight, how other teams could become suspicious
"We regret now the decision of our drivers to wear black helmets... we regret it and we apologise.
"We had our reasons - it was about the lack of bodyguard and security personnel. We do acknowledge that this part of the test aroused suspicions and it is regrettable."
While much has been made about whether or not other teams were either invited to or informed about the test by Pirelli, Mercedes team principal Ross Brawn said his outfit never thought it was its duty to get involved in that matter.
"It was a Pirelli tyre test and it was their authority to do what they wanted in that respect," said Brawn.
When asked if Mercedes had queried with Pirelli about whether or not other teams had been invited, Brawn said: "We did yes. In one of [Andy] Shovlin's statements, he asked if any other teams would be attending the test."
Mercedes is adamant that its running of the 2013 car was not a breach of the regulations because the test was 'undertaken' by Pirelli.
It further believes that a clause in Pirelli's contract with the FIA that allows for private 1000km tests with teams sits outside the sporting regulations.